Android light系统分析

光线系统包括：背光，闪光，led指示灯

 

一.内核层

    Led-class.c (kernel-3.10\drivers\leds) 这个文件给HAL层提供接口

    led_brightness_store是sysfs文件，在"/sys/class/leds/lcd-backlight/brightness"

           __led_set_brightness(led_cdev, i);

                  led_cdev->brightness_set(led_cdev, value); （Leds.h (kernel-3.10\drivers\leds)）

 

         

   led_cdev->brightness_set在Leds_drv.c (kernel-3.10\drivers\misc\mediatek\leds)中的probe函数中被赋值

       g_leds_data[i]->cdev.brightness_set = mt65xx_led_set; 

 

 

mt65xx_led_set 

    mt_mt65xx_led_set(led_cdev, level);  

            mt_mt65xx_led_set_cust(&led_data->cust, led_data->level);   在Leds.c (kernel-3.10\drivers\misc\mediatek\leds\mt6735) 中

       

    mt_mt65xx_led_set_cust //因为我们是GPIO模式，所以就会进入这个分支

             case MT65XX_LED_MODE_GPIO:

LEDS_DEBUG("brightness_set_cust:go GPIO mode!!!!!\n");

return ((cust_set_brightness)(cust->data))(level);

 

    cust->data这个函数指针在Cust_leds.c (kernel-3.10\drivers\misc\mediatek\mach\mt6735\lentek6735_65c_l\leds\mt65xx)被赋值

        static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {

{"red",               MT65XX_LED_MODE_PMIC, MT65XX_LED_PMIC_NLED_ISINK0,{0}},

{"blue",             MT65XX_LED_MODE_NONE, -1,{0}},

{"green",              MT65XX_LED_MODE_PMIC, MT65XX_LED_PMIC_NLED_ISINK1,{0}},

{"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},

{"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},

{"button-backlight",  MT65XX_LED_MODE_NONE, -1,{0}},

{"lcd-backlight",     MT65XX_LED_MODE_GPIO, (long)Cust_Tintele_SetBacklight,{0}},

{"flashlight",        MT65XX_LED_MODE_GPIO, (long)Cust_Tintele_SetFlashlight,{0}},

        };

        

    因为是16节的控制芯片，就是只有16级亮度，用io模拟这种进行控制

        for (; i<=16-level; i++) {

                mt_set_gpio_out(GPIO_LCD_BACKLIGHT_EN | 0x80000000, 0);  

                udelay(2);

                mt_set_gpio_out(GPIO_LCD_BACKLIGHT_EN | 0x80000000, 1);

                udelay(2);

        }

    GPIO_LCD_BACKLIGHT_EN | 0x80000000  //是为了让这个执行更快

 

 

 

 

二.hal层

    Lights.c (vendor\mediatek\proprietary\hardware\liblights)

    set_light_backlight

         write_int(LCD_FILE, brightness);  //LCD_FILE就是/sys/class/leds/lcd-backlight/brightness

    

提供接口给中间层

struct hw_module_t HAL_MODULE_INFO_SYM = {

    .tag = HARDWARE_MODULE_TAG,

    //.version_major = 1,

    //.version_minor = 0,

    .id = LIGHTS_HARDWARE_MODULE_ID,

    .name = "MTK lights Module",

    .author = "MediaTek",

    .methods = &lights_module_methods,

};

 

打开函数

static struct hw_module_methods_t lights_module_methods = {

    .open =  open_lights,

};

 

open_lights

     if (0 == strcmp(LIGHT_ID_BACKLIGHT, name)) {

        set_light = set_light_backlight;

    }

 

 

 

三.jni层

init_native

    hw_get_module(LIGHTS_HARDWARE_MODULE_ID, (hw_module_t const**)&module); //获得hal层的接口

         get_device(module, LIGHT_ID_BACKLIGHT);

              module->methods->open(module, name, &device); //调用hal层的open函数

 

        finalize_native 和 setLight_native上层可以调用、

 

    static JNINativeMethod method_table[] = {

    { "init_native", "()J", (void*)init_native },

    { "finalize_native", "(J)V", (void*)finalize_native },

    { "setLight_native", "(JIIIIII)V", (void*)setLight_native },

    };

 

int register_android_server_LightsService(JNIEnv *env)

{

    return jniRegisterNativeMethods(env, "com/android/server/lights/LightsService",

            method_table, NELEM(method_table));

}

 

 

 

 

四.framework层

   DisplayPowerController.java (frameworks\base\services\core\java\com\android\server\display)

 // Brightness animation ramp rate in brightness units per second.

    private static final int BRIGHTNESS_RAMP_RATE_FAST = 20000;

    private static final int BRIGHTNESS_RAMP_RATE_SLOW = 2000;

 

我要改变拉动背光条，中间过滤一些数值